Stacked Porous Body Cooler for High Heat Flux
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Solution Overview
Problem
Conventional pool boiling system coolers face a critical heat flux limitation of about 1000 kW/m², which is insufficient to prevent melt-through of the bottom part of a light-water reactor pressure vessel, necessitating a more effective cooling mechanism.
Innovation Solution
A boiling system cooler with a stacked structure comprising a first porous body on the heat generation element side and a second porous body with higher permeability on the working fluid side, utilizing capillary action for fluid supply and vapor discharge, enhances cooling efficiency by preventing dryout and increasing critical heat flux to at least 2000 kW/m².
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pool boiling system cooler is used, then the structure is simple and energy consumption is low, but the critical heat flux is limited to about 1000 kW/m² which is insufficient to prevent melt-through
Solution Approach 1:
The patent applies porous materials by providing a porous body in the cooling mechanism. The porous body enables capillary action to supply working fluid to the contact part, allowing the system to achieve a critical heat flux of 2000 kW/m² or more while maintaining structural simplicity. The porous structure facilitates automatic fluid supply without external pumps, resolving the contradiction between improved cooling effectiveness and structural complexity.
2Power
If the heat flux is increased to improve cooling capacity, then the vaporization amount increases, but the contact part becomes covered with vapor causing dryout and remarkable deterioration of cooling capacity
Solution Approach 1:
The porous body enables continuous capillary supply of working fluid to the contact part, preventing vapor accumulation and dryout even at high heat flux conditions. This maintains stable cooling performance and prevents the deterioration that occurs in conventional systems when heat flux increases.
Solution Approach 2:
The patent changes the physical parameters of the cooling system by introducing a porous body with specific capillary properties, which fundamentally alters the fluid supply mechanism from passive convection to active capillary-driven flow, enabling stable operation at higher heat flux levels.
3Reliability
If a porous body is provided to increase critical heat flux, then the cooling effect is improved, but the structure becomes more complex
Solution Approach 1:
The porous body is integrated directly into the cooling mechanism without requiring additional external components such as pumps or complex flow control systems. The capillary action occurs naturally within the porous structure, achieving enhanced critical heat flux while maintaining relative structural simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The enhanced cooling system achieves a critical heat flux of 2000 kW/m² or more, preventing melt-through, while maintaining a simple structure without the need for external power sources or flow passages, reducing installation and running costs.
Implementation Method 1
a first working fluid supply part supplying the working fluid, by capillary action, to a contact part which is in contact with the heat generation element
Implementation Method 2
When heat is generated in the heat generation element, and transmitted to the working fluid through the contact part, the working fluid which is present near the contact part is boiled
Implementation Method 3
When vapor is generated by the boiling, the working fluid is supplied to the contact part according to a difference between a gas density and a liquid density. The working fluid thus newly supplied is further vaporized to remove the heat from the heat generation element
Data Source
Figure 1~2
Figure 3~4
Figure 5(A)~5(C)
AI summary
There is provided a cooler which has a simple structure and stably exhibits a good cooling effect. A cooler includes: a container accommodating a working fluid; and a cooling member provided in the container so as to be brought into contact with the working fluid and to face a heat generation element. The cooling member has a stacked structure including a first porous body provided on the heat generation element side and a second porous body provided on the working fluid side. The first porous body includes: a first working fluid supply part supplying the working fluid, by capillary action, to a contact part which is in contact with the heat generation element; and a first vapor discharge part discharging vapor generated in the contact part to the second porous body side. The second porous body includes: a second working fluid supply part supplying the working fluid to the first porous body; and a second vapor discharge part discharging the vapor discharged from the first porous body, into the working fluid. The second porous body has a higher permeability of the working fluid compared with the first porous body.